[EM] Voter strategising ability

Kristofer Munsterhjelm km_elmet at t-online.de
Thu Jul 24 12:47:41 PDT 2014


On 07/24/2014 06:11 AM, robert bristow-johnson wrote:

> but the *data* doesn't give a rat's ass *how* it's counted or
> tabulated.  can't we use the data from all ranked-choice elections
> (which, in government, would be IRV or RCV or AV or STV or Hare) and see
> how they would work out with Condorcet-compliant rules?  like we did for
> Burlington 2009.  that was a 4-way election close enough that the
> Plurality (of 1st choice votes) winner, the IRV winner, and the
> Condorcet winner were three different candidates.  and yet there was
> *no* cycle.  not even close to a cycle.

Right, but if the data isn't from a Condorcet election, those who think 
Condorcet is vulnerable can just claim that the voters would adjust 
their strategy to the methods in question. Because IRV is relatively 
hard to strategize, they could claim the lack of obvious strategy in IRV 
as evidence of this -- or if there *is* strategy, that the voters will 
strategize no matter what, and therefore the method needs to deter even 
otherwise implausible strategy from the very beginning.

> are there any other ranked-choice elections where media or research
> could access the anonymous ballot data and see if there would have been
> a cycle and then see how Shulze and Tideman and Minimax and Kemeny would
> have been different?  i think we would virtually never see a cycle.  and
> *more* than virtually, i think we would *never* see a cycle with more
> than 3 in the Smith set.

There are lots of polls. For instance, Green-Armytage used data from a 
political barometer (with Range scores) as basis for one of his strategy 
calculations. There are also a number of groups and associations that 
use Condorcet methods (often Schulze, and often related to Debian, which 
first started to use it); and many of these make the votes public.

I have mentioned Debian before, but I have also heard arguments against 
it on the grounds that Debian voters are "obviously different from 
politically polarized general voters" and so that piece of data doesn't 
count.

I also think San Francisco provides ballot data for their elections, but 
I'm unsure of this. I also seem to recall that the general pattern is 
that Plurality is pretty bad at electing the CW, IRV is somewhat better, 
and Condorcet (obviously) elects the CW when there is one.


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